java代码实现过滤器解决CSRF问题

是的，Java代码可以实现过滤器来解决CSRF（跨站请求伪造）问题。可以使用Java Servlet中的Filter接口来实现此过滤器。在过滤器中，可以检查请求的来源，并验证请求是否来自合法的来源。如果请求不来自合法的来源，则可以拒绝该请求。此外，还可以在请求中添加CSRF令牌来验证请求的合法性。这样可以有效地防止CSRF攻击。

相关问题

java csrf filter 示例代码

下面是一个使用 Java 编写的 CSRF 过滤器的示例代码：

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.util.UUID;

public class CsrfFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        // 初始化操作，如果需要的话
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest httpRequest = (HttpServletRequest) request;
        HttpServletResponse httpResponse = (HttpServletResponse) response;

        if (httpRequest.getMethod().equalsIgnoreCase("POST")) {
            HttpSession session = httpRequest.getSession(false);
            String csrfToken = httpRequest.getParameter("csrfToken");
            
            if (session == null || csrfToken == null || !csrfToken.equals(session.getAttribute("csrfToken"))) {
                httpResponse.sendError(HttpServletResponse.SC_FORBIDDEN, "Invalid CSRF Token");
                return;
            }
        }

        chain.doFilter(request, response);
    }

    @Override
    public void destroy() {
        // 销毁操作，如果需要的话
    }
}

在上述示例中，`CsrfFilter` 是一个实现了 `javax.servlet.Filter` 接口的过滤器。它会拦截所有的请求，并在 POST 请求中验证 CSRF 令牌的有效性。

你可以在 `web.xml` 文件中配置该过滤器，例如：

<filter>
    <filter-name>CsrfFilter</filter-name>
    <filter-class>com.example.CsrfFilter</filter-class>
</filter>

<filter-mapping>
    <filter-name>CsrfFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

这样，所有的请求都会通过 `CsrfFilter` 进行过滤，并在需要的时候进行 CSRF 令牌的验证。

请注意，这只是一个简单的示例，你可能需要根据你的应用程序和框架进行适当的调整。确保在生成 CSRF 令牌时使用安全的随机数生成算法，并在验证令牌时采取适当的安全措施。

微信小程序使用springsecurity和jwt实现权限验证java代码

以下是微信小程序使用Spring Security和JWT实现权限验证的Java代码示例：

1. 配置Spring Security

创建一个SecurityConfig类，配置Spring Security的基本设置和JWT过滤器：

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Autowired
    private JwtAuthenticationEntryPoint jwtAuthenticationEntryPoint;

    @Autowired
    private JwtAuthorizationTokenFilter jwtAuthorizationTokenFilter;

    @Autowired
    private UserDetailsService userDetailsService;

    @Autowired
    public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
        auth.userDetailsService(userDetailsService).passwordEncoder(passwordEncoder());
    }

    @Bean
    public PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }

    @Bean
    @Override
    public AuthenticationManager authenticationManagerBean() throws Exception {
        return super.authenticationManagerBean();
    }

    @Override
    protected void configure(HttpSecurity httpSecurity) throws Exception {
        httpSecurity.csrf().disable()
                .authorizeRequests()
                .antMatchers("/api/auth/**").permitAll()
                .anyRequest().authenticated()
                .and()
                .exceptionHandling().authenticationEntryPoint(jwtAuthenticationEntryPoint)
                .and()
                .sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS);

        httpSecurity.addFilterBefore(jwtAuthorizationTokenFilter, UsernamePasswordAuthenticationFilter.class);
        httpSecurity.headers().cacheControl();
    }

    @Override
    public void configure(WebSecurity webSecurity) throws Exception {
        webSecurity.ignoring().antMatchers(HttpMethod.POST, "/api/auth/login");
    }
}

2. 创建JWT工具类

创建一个JwtTokenUtil类，用于处理JWT的生成、解析和验证：

@Component
public class JwtTokenUtil {

    private static final Logger logger = LoggerFactory.getLogger(JwtTokenUtil.class);

    private static final String CLAIM_KEY_USERNAME = "sub";
    private static final String CLAIM_KEY_CREATED = "iat";
    private static final String CLAIM_KEY_EXPIRED = "exp";

    @Value("${jwt.secret}")
    private String secret;

    @Value("${jwt.expiration}")
    private Long expiration;

    public String getUsernameFromToken(String token) {
        String username;
        try {
            final Claims claims = getClaimsFromToken(token);
            username = claims.getSubject();
        } catch (Exception e) {
            username = null;
        }
        return username;
    }

    public Date getCreatedDateFromToken(String token) {
        Date created;
        try {
            final Claims claims = getClaimsFromToken(token);
            created = new Date((Long) claims.get(CLAIM_KEY_CREATED));
        } catch (Exception e) {
            created = null;
        }
        return created;
    }

    public Date getExpirationDateFromToken(String token) {
        Date expiration;
        try {
            final Claims claims = getClaimsFromToken(token);
            expiration = claims.getExpiration();
        } catch (Exception e) {
            expiration = null;
        }
        return expiration;
    }

    private Claims getClaimsFromToken(String token) {
        Claims claims;
        try {
            claims = Jwts.parser().setSigningKey(secret).parseClaimsJws(token).getBody();
        } catch (Exception e) {
            claims = null;
        }
        return claims;
    }

    private Date generateExpirationDate() {
        return new Date(System.currentTimeMillis() + expiration * 1000);
    }

    private Boolean isTokenExpired(String token) {
        final Date expiration = getExpirationDateFromToken(token);
        return expiration.before(new Date());
    }

    public String generateToken(UserDetails userDetails) {
        Map<String, Object> claims = new HashMap<>();
        claims.put(CLAIM_KEY_USERNAME, userDetails.getUsername());
        claims.put(CLAIM_KEY_CREATED, new Date());
        return generateToken(claims);
    }

    private String generateToken(Map<String, Object> claims) {
        return Jwts.builder()
                .setClaims(claims)
                .setExpiration(generateExpirationDate())
                .signWith(SignatureAlgorithm.HS512, secret)
                .compact();
    }

    public Boolean canTokenBeRefreshed(String token) {
        return !isTokenExpired(token);
    }

    public String refreshToken(String token) {
        String refreshedToken;
        try {
            final Claims claims = getClaimsFromToken(token);
            claims.put(CLAIM_KEY_CREATED, new Date());
            refreshedToken = generateToken(claims);
        } catch (Exception e) {
            refreshedToken = null;
        }
        return refreshedToken;
    }

    public Boolean validateToken(String token, UserDetails userDetails) {
        JwtUser user = (JwtUser) userDetails;
        final String username = getUsernameFromToken(token);
        return (
                username.equals(user.getUsername())
                        && !isTokenExpired(token));
    }
}

3. 创建JWT过滤器

创建一个JwtAuthorizationTokenFilter类，用于处理JWT的解析和验证：

@Component
public class JwtAuthorizationTokenFilter extends OncePerRequestFilter {

    private final Logger logger = LoggerFactory.getLogger(this.getClass());

    @Autowired
    private JwtTokenUtil jwtTokenUtil;

    @Autowired
    private UserDetailsService userDetailsService;

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws ServletException, IOException {
        logger.debug("processing authentication for '{}'", request.getRequestURL());

        final String requestHeader = request.getHeader("Authorization");

        String username = null;
        String authToken = null;
        if (requestHeader != null && requestHeader.startsWith("Bearer ")) {
            authToken = requestHeader.substring(7);
            try {
                username = jwtTokenUtil.getUsernameFromToken(authToken);
            } catch (IllegalArgumentException e) {
                logger.error("an error occured during getting username from token", e);
            } catch (ExpiredJwtException e) {
                logger.warn("the token is expired and not valid anymore", e);
            }
        } else {
            logger.warn("couldn't find bearer string, will ignore the header");
        }

        logger.debug("checking authentication for user '{}'", username);
        if (username != null && SecurityContextHolder.getContext().getAuthentication() == null) {
            UserDetails userDetails = this.userDetailsService.loadUserByUsername(username);
            if (jwtTokenUtil.validateToken(authToken, userDetails)) {
                UsernamePasswordAuthenticationToken authentication = new UsernamePasswordAuthenticationToken(userDetails, null, userDetails.getAuthorities());
                authentication.setDetails(new WebAuthenticationDetailsSource().buildDetails(request));
                logger.info("authenticated user '{}', setting security context", username);
                SecurityContextHolder.getContext().setAuthentication(authentication);
            }
        }

        chain.doFilter(request, response);
    }
}

4. 创建JWT用户类

创建一个JwtUser类，实现Spring Security的UserDetails接口：

public class JwtUser implements UserDetails {

    private final Long id;
    private final String username;
    private final String password;
    private final Collection<? extends GrantedAuthority> authorities;
    private final boolean enabled;
    private final Date lastPasswordResetDate;

    public JwtUser(
            Long id,
            String username,
            String password,
            Collection<? extends GrantedAuthority> authorities,
            boolean enabled,
            Date lastPasswordResetDate
    ) {
        this.id = id;
        this.username = username;
        this.password = password;
        this.authorities = authorities;
        this.enabled = enabled;
        this.lastPasswordResetDate = lastPasswordResetDate;
    }

    @JsonIgnore
    public Long getId() {
        return id;
    }

    @Override
    public String getUsername() {
        return username;
    }

    @JsonIgnore
    @Override
    public boolean isAccountNonExpired() {
        return true;
    }

    @JsonIgnore
    @Override
    public boolean isAccountNonLocked() {
        return true;
    }

    @JsonIgnore
    @Override
    public boolean isCredentialsNonExpired() {
        return true;
    }

    @JsonIgnore
    @Override
    public String getPassword() {
        return password;
    }

    @Override
    public Collection<? extends GrantedAuthority> getAuthorities() {
        return authorities;
    }

    @Override
    public boolean isEnabled() {
        return enabled;
    }

    @JsonIgnore
    public Date getLastPasswordResetDate() {
        return lastPasswordResetDate;
    }
}

5. 创建登录控制器

创建一个AuthController类，用于处理用户登录和令牌的生成：

@RestController
@RequestMapping("/api/auth")
public class AuthController {

    private final Logger logger = LoggerFactory.getLogger(this.getClass());

    @Autowired
    private AuthenticationManager authenticationManager;

    @Autowired
    private JwtTokenUtil jwtTokenUtil;

    @Autowired
    private UserDetailsService userDetailsService;

    @PostMapping("/login")
    public ResponseEntity<?> createAuthenticationToken(@RequestBody JwtAuthenticationRequest authenticationRequest) throws AuthenticationException {
        logger.info("authenticating user '{}'", authenticationRequest.getUsername());

        final Authentication authentication = authenticationManager.authenticate(
                new UsernamePasswordAuthenticationToken(
                        authenticationRequest.getUsername(),
                        authenticationRequest.getPassword()
                )
        );
        SecurityContextHolder.getContext().setAuthentication(authentication);

        final UserDetails userDetails = userDetailsService.loadUserByUsername(authenticationRequest.getUsername());
        final String token = jwtTokenUtil.generateToken(userDetails);

        return ResponseEntity.ok(new JwtAuthenticationResponse(token));
    }
}

6. 创建异常处理器

创建一个JwtAuthenticationEntryPoint类，用于处理不允许访问的请求：

@Component
public class JwtAuthenticationEntryPoint implements AuthenticationEntryPoint {

    private final Logger logger = LoggerFactory.getLogger(this.getClass());

    @Override
    public void commence(HttpServletRequest request, HttpServletResponse response, AuthenticationException authException) throws IOException {
        logger.error("unauthorized error: {}", authException.getMessage());
        response.sendError(HttpServletResponse.SC_UNAUTHORIZED, "Unauthorized");
    }
}

7. 创建请求对象

创建一个JwtAuthenticationRequest类，用于保存用户登录请求：

public class JwtAuthenticationRequest implements Serializable {

    private static final long serialVersionUID = -8445943548965154778L;

    @NotBlank
    private String username;

    @NotBlank
    private String password;

    public JwtAuthenticationRequest() {
        super();
    }

    public JwtAuthenticationRequest(String username, String password) {
        this.setUsername(username);
        this.setPassword(password);
    }

    public String getUsername() {
        return this.username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return this.password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

8. 创建响应对象

创建一个JwtAuthenticationResponse类，用于保存令牌响应：

public class JwtAuthenticationResponse implements Serializable {

    private static final long serialVersionUID = 1250166508152483573L;

    private final String token;

    public JwtAuthenticationResponse(String token) {
        this.token = token;
    }

    public String getToken() {
        return this.token;
    }
}

以上是微信小程序使用Spring Security和JWT实现权限验证的Java代码示例，希望能对你有所帮助。